Radar Performance Degradation in Fog and Rain

An equation is derived which can be used to compare the ability of a pulse radar to detect targets in rain and fog with its ability to detect similar targets in dry air. It is a common misconception that attenuation in the path between radar and target is the only consideration. However, clutter in the path between radar and target is the real concern. Clutter power backscattered from the storm in the immediate region of the target may be by far the most dominant degrading factor. The equation derived, and the resulting curves, take into consideration the combined effects of backscattering and attenuation and interpret the effects in terms of comparative dry-air and wet-air range capability. They enable 1) prediction of the relative performance of a given radar under various meteorological conditions, and 2) comparison of radars of different parameters operating under identical meteorological conditions.